Constructor of Useful Parsers (CUP) - Generates LALR parsers from simple specifications. [Open Source] SableCC - Object-oriented framework, written in Java, that generates compilers (and source-interpreters) for Java. [Open Source, LGPL] JFlex - Lexical analyzer generator (also known as scanner generator) for Java, written in Java. A rewrite of JLex with more features. [Open Source, GPL] Modern Compiler Implementation in Java - JLex and CUP, Andrew Appel's Lex and YACC equivalents. LALR parser generators. The tools are free, the book their use is described in can be ordered here. [Freeware] JELLRAP - The Java Enhanced LL LR Animated Parser is a graphical tool to parse strings using a variety of algorithms; LLParse and LRParse combined into a single tool that will run on multiple platforms. [Open Source] Coco/R for Java - Takes as input a compiler description in the form of an LL(1) attributed grammar and generates a scanner and parser. [Freeware] Beaver - A LALR(1) parser generator. Uses very fast (based on perfect hashing) parsing engine. [Open source, LGPL] BNF for Java - BNF compiler-compiler is designed to conform to ISO-14977. It is implemented in Java, for Java programmers. [Open source, GPL]